moldy/musty smelling water

Hello, we just bought a 50 yr old home about a month ago, and have noticed a musty, moldy smell to the water when you turn it on and while it runs for the first few minutes. While in the shower it seems to go away while you are in but if you walk back into the bathroom after drying off it is still very strong so I think you just get used to the smell very quickly. The master bath has been under repair so it hasn't gotten used much since we have moved in. The wife used it yesterday and the hot water come out orange and the smell was the strongest it has ever been. Everything I have researched having to do with smelly water has been a sulfur/rotten egg smell which this is not. Does anyone have an idea of what is wrong or how fix to it. Could it just be old rusty pipes? There is no apparent moisture issues in any of the bathrooms or in the kitchen. Thanks in advance.

Yes I do not believe it is the sulfur smell though I do plan on chloronating the water heater, I figure it can't hurt. I do get it from all fixtures and even from the toilets but much less noticeably. I have't asked the neighbors yet, we have been completely consumed with this house getting it up to snuff not to mention we have 2 little girls under two years old. I did run into the previous owner at Home Depot and he said he never noticed the smell, so I don't know if it is a new issue or they were just used to the odor. The house did sit for a month or so before we move in after closing. We were painting and such before we moved in. I just recently replaced the kitchen faucet and the smell is no where near as bad. Can some sort of mold build up inside the pipes? The water heater is 6 yrs old and I have drained it once. I figured the orange water was rust and we only noticed it in the bath room that has not been in regular use. As far as I can tell the inlets to all the sinks are galvanized, I know the water heater is copper. I would have to go under the house to see what the showers are though. We are on city water. Thanks for the reply and follow up questions. I would love to figure out what is cousing this smell.

Galvanized rusts...when you run water through it every day, you may not notice, but if you let it sit, it will increase its concentration. It could also be coming from the hot water heater as a separate source (you said it was copper - did you mean the supply pipes at its location?). You could try draining the hot water tank (shut off the power/fuel first and don't turn it on until it is full again, though). If the supply line from the city was galvanized, too, then it could have a good accumulation in it as well. Try flushing it out by running your hose for awhile - got any flowers to water?(often the highest flow you get in a house).

I understand why the unused bathroom had the rust. Is it ok to be drinking, making baby bottles with water with the rust in it? Would the rust be causing the smell? I have already flushed the heater once since we moved in. Yes copper supply lines to the water heater.

The rusty water can be from any galvanized in the plumbing or iron in the water.

The odor can be naturally occurring H2S (sulfur) coming in with the water from the well OR if not, then bacteria such as IRB, SRB or MRB (iron, sulfate or manganese reducing bacteria). They are harmless but cause quite an odor. They can colonize a softener, filter or water heater with the temp set less than 140f.

If bacteria is the cause, you must kill them. If H2S in the water from the well, you must oxidize it and there are a number of ways to do either. I like an inline erosion pellet chlorinator, special mixing tank with a bottom drain and following that, a backwashed Centaur carbon filter. That system kills and oxidizes and has very little maintenance requirements.

Check the water line and below it in the most frequently used toilet for any color or clear slime. If you find an oily film on the water or slime, you have a reducing bacteria problem.

Thanks Gary,
Checked the toilet no slime. I have read alot about the rotten egg(sulfur) smell and this is NOT what we are smelling. It smells moldly or musty like a damp basement would smell, but it is coming from the pipes some how. One other note. While searching the net some thing said to put the water in a cup and take it our of the room and smell it. It isn't the water b/c if you smell the water by itself there is no smell. Totally confused on what this is.

Might it be one of the drains in the house has dried out? If it was unoccupied for a month, maybe a floor drain or something. Go all around the house, run water in each thing that has a drain, including the washing machine. Then, search the basement for floor drains, run water into each of them from a bucket.

If a trap has dried out, running any water will move sewer gasses out of it and into the house.

Thanks Jim,
Ok I will try that, all inside drains have been in use since we have moved in except the master bath so that may be the culprit if your theory is right. Now about the floor drains. I have a crawl not a basement. Am I correct to assume there would not be any drains down there. I no what happens when you assume though.
Thanks,
Erik

Could also be a minor drain leak withing a wall or floor leaving a damp surface. It could even be from a past leak repaired before sale of house. You would not smell this after about 5-10 minutes in the room as your senses become accustomed to the smell and dismisses it.

Thanks all, pouring water and bleach down the drains didn't seem to make a difference. vaplumber, how would I go about diagnosing if there is dampness/mold inside the walls or under the floors? If thisis the problem would turning the water on increase the odor? You can walk into the bath and not notice the smell, but then you turn on the water to fill the tub and boy does it get strong. You guys are great, thanks for all the help.

... You can walk into the bath and not notice the smell, but then you turn on the water to fill the tub and boy does it get strong. You guys are great, thanks for all the help.

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That proves the odor is in the water. It comes out of solution as the water is depressurized and aerated. You need to identify the odor; IIRC you said it wasn't 'sulfur' (H2S rotten egg).

You can't move the glass of water and keep the air in the gas on top of the water and then smell the odor later... the air movement will dissipate the odor as you walk and it only takes a few seconds for the odor to be gone.

Run just cold water in the tub and kneel down and smell the air coming out of the tub for the odor. My guess is that it will be present but... if not, drain the tub and in 15-20 minutes, repeat using only hot water. If the odor is in the hot water only, it is caused by SRB (sulfate reducing bacteria). Turn up the temp on the heater to 140f for an hour or more and check it again.